FIG. 1 is a flow chart depicting a conventional method 10 for fabricating a conventional perpendicular magnetic recording (PMR) transducer. For simplicity, some steps are omitted. The conventional method 10 is used for providing a PMR pole. An intermediate layer is provided, via step 12. The intermediate layer is typically aluminum oxide. A mask is provided on the aluminum oxide layer, via step 14. The mask may be a hard mask patterned using a photoresist mask. The mask includes an aperture above the portion of the aluminum oxide layer in which the PMR pole is to be formed. Using the mask, a trench is formed in the aluminum oxide layer, via step 16. The top of the trench is wider than the trench bottom. In addition, the trench may extend through the aluminum oxide layer to the underlayer. As a result, the PMR pole formed therein will have its top surface wider than its bottom. Consequently, the sidewalls of the PMR pole have a reverse angle.
The conventional PMR pole materials are deposited, via step 18. Step 18 may include plating or sputtering ferromagnetic pole materials as well as seed layer(s). In addition, nonmagnetic and seed layers may be deposited prior to the conventional PMR pole materials. A single chemical mechanical planarization (CMP) is then performed, via step 20. The single CMP may be performed after an insulating refill layer has also been deposited over the pole materials. The CMP is performed such that the insulating and pole materials may be removed at a sufficiently high rate to have a desired throughput. For example, a down force of at least three psi and in some cases four to six psi may be used. In addition, a slurry appropriate for the materials being removed and the desired time may be used in the CMP. Such a CMP may remove approximately sixty nanometers of aluminum oxide deposited on the pole materials in approximately five through fifteen seconds. The pole may be milled to its final height, via step 22. Subsequent structures, such as a write gap and shields, may also be fabricated.
Although the conventional method 10 may provide a conventional PMR transducer, there may be drawbacks. Despite the CMP, there are variations in the height of the pole after the CMP is performed. For example, dishing in the pole region may occur. These variations may be magnified by the ion mill performed in step 22. Thus, the height and width of the pole may vary. Further, the method 10 may be difficult to scale to even higher areal densities. Accordingly, what is needed is an improved method for fabricating a PMR transducer.